For example, Japanese Patent No. 3010141 discloses a sealed electric refrigerant compressor, which will be described with reference to FIG. 8. The sealed electric compressor 101 includes a metal lower housing 102A in which are housed a compressor 103 and an electric motor 104 driving the compressor 103. The lower housing 102A has an opening, and an upper housing 102B is welded to the lower housing 102A along an entire periphery of the opening in a gastight manner, whereby a sealed housing is constituted.
A suction pipe 105 for introducing refrigerant into the compressor 103 extends through the lower housing 102A. A discharge pipe 106 through which compressed refrigerant is supplied to an external heat exchanger (not shown) or the like extends through the upper housing 102B to be fixed. Furthermore, the upper housing 102B is provided with a hermetic terminal 107 for connecting the motor 104 in the sealed housing and an external power source (not shown). A plurality of electrically conductive terminal pins 107A extend through a metal plate constituting the hermetic terminal 107. These plural terminal pins 107 are hermetically insulated and fixed by an electrically insulative sealing material such as glass. A lead wire 108 and a thermally responsive protector 109 both to be connected to a winding of the motor 104 are connected to a part of the conductive terminal pin 107A located inside the sealed housing.
The thermally responsive protector 109 has a thermally responsive contact mechanism (a thermally responsive switch) comprising a thermally responsive element such as a bimetal. The thermally responsive protector 109 is connected in series to the motor 104 which is energized with an operating current. Furthermore, the thermally responsive protector 109 is directly exposed to the refrigerant in the sealed housing. Accordingly, when overcurrent flows in the motor 104 for any cause or when an ambient temperature rises for any cause, the thermally responsive protector 109 is operated to interrupt energization of the motor 104. As a result, the motor 104 can be prevented from overheat or burning due to overload or overcurrent.